# Factorial, Fibonacci and Prime Number in C++ Program

Write a program in C++ that : i) prints the factorial of a given number ii) prints weather a number is prime or not iii) generate a Fibonacci series of 20 numbers.

```#include <iostream>
using namespace std;

int main()
{
int choice, n;
cout << "1. Factorial of given number \n";
cout << "2. Test Prime Number \n";
cout << "3. Generate Fibonacci series \n";
cout << "Enter choice";
cin >> choice;
switch (choice)
{
case 1:
{
int fact = 1;
cout << "Enter number ";
cin >> n;
for (int i = 1; i <= n; i++)
fact = fact * i;
cout << "Factorial is " << fact;
}
break;
case 2:
{
int flag = 0;
cout << "Enter number ";
cin >> n;
for (int i = 2; i < n; i++)
{
if (n % i == 0)
{
cout << "Number is not prime ";
flag = 1;
break;
}
}
if (flag == 0)
cout << "Number is prime";
}
break;
case 3:
int first = 0, second = 1, third;
cout << first << " " << second << " ";
for (int i = 3; i <= 20; i++)
{
third = first + second;
cout << third << " ";
first = second;
second = third;
}
}
return 0;
}
```